What you propose would again only apply to non criminals. You proposed that gun shop owners keep a ledger, with a state to state time period for keeping that ledger. Let’s say a “reasonable”’time period for keeping a ledger is 10 years of record keeping (this isn’t all that reasonable considering if you’ve owned a gun for 9 years, chances are extremely low you’ll commit a crime with it on the 10th year). So I buy a 11 year old gun, and say I got it for some other shop when it was hot off the assembly line. Oh too bad, no record for it there, sorry officer. This is why you need a gun registry. If you have a gun registry, LE has something to compare your story too. Were taking about every single gun circulating in the US, not just one type of gun. There are more privately owned guns in the US than there are people in the US. It’s not like scrapping a gun is more profitable than selling it. There also no way to know someone lost their gun without a gun registry. If I lost my gun hiking in the woods, I’m not going to turn myself into the police station for that if they have no way to know that I owned that gun.